The Assabet River Rail Trail (ARRT) offers hikers, bicyclists,
and other users the opportunity to experience numerous natural resources
common to our region. This guide identifies the most significant natural
resources along the 12.5-mile trail as it passes through Marlborough, Hudson,
Stow, Maynard, and South Acton in eastern Massachusetts. It begins in Marlborough
and finishes in Acton (purely for convenience sake) as if one were to walk
from one end of the trail to the other.

This guide has two main objectives:

(1.) To inventory the existing natural resources along
the ARRT greenway and identify key flora and fauna within the proposed
pedestrian trail. More specifically, to identify habitats supporting populations
of species classified as rare or endangered that could require modifying
the proposed ARRT route.

(2.) To prepare a guide that can help introduce us to
the diversity of nature in our "backyards."

In response to the first objective, the natural resources
discussed in this guide include: surface geology and soils, water, water
supplies, flood plains, wetlands, plants, animals, endangered species habitats,
topographical features, vistas, and adjacent open spaces. One location
along the ARRT is home to a listed species of special concern; see eastern
Hudson and western Stow for estimated habitat identification. More research
will need to be done to determine exactly what impact this natural treasure
will have on trail alignment and design.

In Marlborough, Hudson, and Maynard the trail runs through
lands that are mostly urbanized; in Stow and Acton, the trail is located
in predominantly rural areas with more natural resources. From one end
to the other, the ARRT follows the path of a former railroad R.O.W. - the
Old Marlborough Branch, which went out of service in 1973. As an abandoned
railroad bed (some segments still retaining the steel track and railroad
ties), the entire ARRT rail line is a human-altered feature of our landscape.

Much of this neglected R.O.W. of the Marlborough Branch
has become over-grown with a mix of native and introduced or invasive plant
species. This gives the trail a 'natural" feeling, especially when experienced
in conjunction with its urban or suburban surroundings.

II.

The most signifigant natural resource along the ARRT is
of course the Assabet River. The trail follows the river valley in Hudson,
Stow, and Maynard, where opportunities exist to walk the trail directly
along the river's edge. It is no surprise that the railroad followed the
generally lazy course of the Assabet: This route offered the easiest gradient
for running the rail lines. Wetland protection wasn't considered when such
railroads were constructed in the 1840's and early 1850's with maximized
operational efficiency in mind. Today, the earthen berms on which the railroads
ran, especially where they remain in the floodplains along water bodies
are particularly special land forms: They allow the public direct access
to nature without disturbing sensitive environments. This provides a wonderful
opportunity to reconnect with our natural surroundings.

The trail can be enjoyed as an "outdoor environmental
classroom" whether one is traveling through rural or more urbanized stretches
of the ARRT corridor. It is hoped that this guide will encourage further
investigation by students of all ages.

Marlborough

Starting at the site of the former Rail Road Station off Lincoln Street
in downtown Marlborough, the ARRT heads north toward Hudson Street. Located
one block to the northeast is Kelleher Field, a neighborhood park with
a football field, bleachers, and a children's play area.

The highest point along the ARRT is at Hudson Street,
with an elevation of approximately 451.5 feet above mean sea level. This
high point marks the divide between the Sudbury and Assabet watersheds.
Rain falling on the ARRT south of Hudson Street flows into the Sudbury
River, and rain falling on the ARRT north of this point on Hudson Street
flows into the Assabet River. Most of the ARRT is within the Assabet River
watershed.

Beyond Hudson Street, the trail goes through an excavated
cut; exposed bedrock or ledge can be seen on both sides. This reveals the
western shoulder of Okoocanganset Hill, a hilltop shaped by glaciers over
10,000 years ago.

Continuing down the hill and crossing Ash Street, Mt.
Wachusetts can be glimpsed 20 miles to the northwest. This view is best
enjoyed in the winter when the leaves have fallen.

Soon the trail flattens out as it traverses the top of
a thirty-foot-high fill placed by the railroad to facilitate crossing a
drainage swale (see * on map on Page 3.) This drainage path is one of the
headwaters of Sheep Fall Brook to the west and marks the division between
Okoocanganset Hill and Addition Hill. Vegetated wetlands and the buffers
along Sheep Fall Brook are home to a more diverse range of plant and animal
species than encountered along the trail to this point.

Thus far, we have been walking through a very urbanized
area. The vegetation adjacent to neighboring backyards along the trail
includes introduced or invasive species such as Norway maple, burning bush,
and Japanese knotweed. The wildlife is mostly comprised of creatures that
can survive in city conditions, such as gray squirrels, chickadees, and
feral cats.

When we enter the more natural area near Sheep Fall Brook, we observe transitional
plant species, such as black raspberry, poison ivy, and gray birch. Oaks
dominate the tree canopy. Red-tailed fox, woodchuck, raccoon, skunk, red
squirrel, porcupine, and rabbit may be watching you from hidden spots beneath
the vegetation. These woods are also home to birds such as cardinal, mourning
dove, downy woodpecker, tufted titmouse, owls, purple finch, robins, and
woodcock.

After passing Fairbanks Boulevard, the trail skirts along
the western side of a large parcel owned by the City of Marlborough. This
had formerly been the site of a landfill; now part of it is a golf driving
range.

Downhill slightly from the driving range, an opportunity
for a scenic lookout exists, taking in the view of Fort Meadow Reservoir
to the northeast.

As we approach Fitchburg Street, the rail traverses a large fill constructed
by the railroad as a stream crossing. The stream is called Flagg Brook.
It carries water flowing from Sheep Fall Brook and Flagg Swamp, and runoff
shed by Addition Hill. Flagg Brook in turn flows to the east into Fort
Meadow Reservoir Marsh and other vegetated wetlands border Flagg Brook,
and during times of heavy rainfall, flooding occurs along each bank. This
is part of a wildlife corridor. From the trail, sixty feet above Flagg
Brook, we are at level with tree tops. Canopy trees include red oak, white
oak, red maple, black birch, white pine, white ash, and shagbark hickory.
A healthy understory of small trees includes common witchhazel, speckled
alder, highbush blueberry, and spicebush. This wooded corridor is the most
wild and natural site the ARRT encounters in Marlborough. Beavers have
been active in this area recently.

After we cross Fitchburg Street, the trail is bordered
on the right by the Assabet Valley Regional Vocational High School, with
athletic fields directly to the east. A wooded swamp wetlands area is situated
along the trail, just north and west of the football field parking lot.
To the west of the trail is Hager Hill.

Additional natural resources along the ARRT in Marlborough:

Municipal water supply Water Supply Protection DistrictThe ARRT doesn't pass through this resource protection
district; Marlborough's closest municipal water supply is Millham Reservoir
in the western end of the city.

It should be noted, however, that water flowing from Flagg
Brook into Fort Meadow Reservoir and then into Fort Meadow Brook do subsequently
pass through public water supplies in Hudson known as the Chestnut Street
WelIfield.

Rare and Endangered SpeciesWithin the Marlborough locus of the ARRT, there are no rare
or endangered species listed by the Natural Heritage and Endangered Species
Program maps.

Hudson

We enter the town of Hudson as we begin across the Connector
Road. Immediately we disappear into a world of trees along the base of
a steep rocky slope to the west. This hill has no name on the USGS topographic
map, although its top elevation of about 480 plus feet makes it the highest
point in Hudson. To the right of the trail we see areas of shrub swamp,
a favorite home for birds such as red-winged blackbird and marsh wren.

As the trail swings to the left, it passes under an old
over-pass; the large, rugged stone abutments flanking the trail are significant
cultural vestiges of the bygone railroad era.

To the right (or east) of the trail we soon see a wooded
swamp about eight acres in size. This wetland resource is the headwaters
for a small unnamed brook that flows to the northwest. The brook crosses
under the trail, then parallels the trail on the left for approximately
nine hundred feet before disappearing into a recent residential subdivision
and subsequently joining the Assabet River. This segment of trail along
the small brook is very pleasant (if we look past an array of shopping
carts and other debris); it has great potential as a pocket of natural
beauty. Surprisingly, just 30 feet up the steep embankment on our right
are parking and loading docks of adjacent commercial enterprises, such
as the Victory Supermarket.

Soon we cross Washington Street. This portion of the trail
is decidedly urbanized. Species that populate this section of the trail
corridor include invasive plants such as Japanese knotweed and Norway maples,
and urban-tolerant animals such as gray squirrels and rats.

We have been going steadily downhill ever since crossing
Hudson Street in Marlborough. The hills on each side of the trail are generally
comprised of glacial till on bedrock. Between the hills are areas of sand
and gravel; these were deposited and sorted according to particle size
by the meltwater flowing out of the bottom of the melting glaciers. Small
sand particles could be carried a greater distance by the meltwaters and
typically were deposited closer to the Assabet River; larger stones couldn't
be carried as far by meltwaters and often stayed higher up on hillsides.

The next significant natural landmark is the Assabet River.
We traverse a high trestle that crosses the river some 40 feet below. This
is the first occasion for the ARRT to cross the Assabet River. By the time
we reach the Commuter Rail Station in South Acton, the ARRT will cross
the river a total of five times. The river at this point is fairly fast
flowing and relatively rich in oxygen due to turbulence and aeration provided
by the rivers ten foot plunge over the dam 1600 feet upriver at Washington
Street. The river is home to reptiles such as the snapping turtle and the
northern water snake. Fish, including largemouth bass and white sucker
sometimes inhabit the river at this point. Though the water quality has
been improving in recent years, this stretch of river is not yet clean
enough to support populations of more demanding fish such as brook trout.

Soon we come to the second Assabet River crossing, which
offers a pleasant view up and down the river. It is the site of persistent
river clean-up efforts by members of the community who work each spring
to clear branches, logs, car tires, shopping carts, and other debris from
the piers that support Main Street and the railroad bridges. With each
spring flood, a new batch of entanglements are lodged among the piers,
making passage difficult for canoeists and water levels higher during floods.

East of this Assabet River crossing, the trail passes
homes and commercial properties. After crossing Cox Street, the municipal
property for the Mulready School (formerly called the Cox Street School)
can be seen to the left. Wetland areas are present both north and south
of the trail. These merge with broader wooded swamplands to the east. Red
maple and white pine are the dominant canopy trees.

Outflow from a pond within the Rod and Gun property to
the north combines (near Wilkins Street) with a tributary draining wooded
swampland from the south, and gives rise to a small unnamed stream that
flows east into Stow along the trail. East of Wilkins Street the land along
the ARRT becomes more wild and natural than any other trail segment in
Hudson. A large portion of these lands are wetlands.

At about this point, we have entered the Zone II well-head
protection area associated with the Chestnut Street municipal wellfields.

We have also entered an area listed with the Natural Heritage
and Endangered Species Program as home to rare plant and/or wildlife species.
This estimated habitat is roughly 75 acres in area, extending south to
the former Central Massachusetts Railroad line, north to High Street in
Stow, and east to the Assabet River. The exact identity of the species
of special concern is not publicized in this guide in order to help protect
it. Further to the east and to our right, the land rises up to become Gospel
Hill.

Stow

East of the Hudson-Stow line, the trail skirts pockets
of wooded swamp and marsh to the south. This area is part of a 7~acre habitat
listed with the Natural Heritage and Endangered Species program, and therefore
has special significance.

After crossing Marlborough Road, the trail follows Railroad
Avenue to its end at the Assabet River. This is the third river crossing;
actually, the railroad had two bridge spans that used a small island midway
for crossing the river.

The river, its banks, and adjoining landscape in this
vicinity are the most natural that we've encountered so far on our journey
from Marlborough. The river valley is alive with healthy marsh, shrub swamp,
wooded swamp, and a diverse range of habitat for the abundant wildlife.
Amphibians, including a variety of species of frog and red-spotted newts,
inhabit the river's banks. The river valley serves as an important corridor
for waterfowl migration. Here, human influence is minimal and nature dominates
- the reverse of what is experienced on the ARRT in Marlborough, Hudson,
Maynard, and Acton.

We are also within a Water Resource Protection District.
This zoning classification is aimed at protecting a potential well site
roughly 1,000 feet to our north, where exceptionally high groundwater yields
have been documented. This zoning district also protects the Chestnut Street
wellfleld, about 1,200 feet to our south in Hudson.

The proposed trail would next pass through the back land
of Honey Pot Hill Orchards. At this time, it is far from certain if the
family that owns and operates the orchards will allow the ARRT to follow
the old railroad bed through their property. This leaves a gap roughly
nine-tenths of a mile in length before we leave Honey Pot Hill Orchards
and encounter an Assabet River crossing once again. This fourth river crossing
on the proposed trail occurs at a location approximately 1,200 feet upriver
of Sudbury Road. The land along the ARRT continues to be fully natural,
with a diverse mix of riverine and upland habitats and associated wildlife.

By the time we reach Sudbury Road, the Assabet River has
grown with the addition of flows from Fort Meadow Brook and Lake Boon.
The water quality has improved during its slow, meandering passage through
the marshlands south of Honey Pot Hill Orchards.

After crossing Sudbury Road, the ARRT follows what is
locally known as Track Road. This is a private gravel road, approximately
1-3/4 miles in length, extending between Sudbury Road and White Pond Road
at the Stow-Maynard line. To our left we see the Assabet River, complete
with healthy deep marsh and wooded wetland riparian buffer zones.

After walking about half a mile along Track Road we begin
to see the Fort Devan Annex on our right. This property is slated to be
conveyed from the Department of Defense to the U.S. Fish and Wildlife Department
and become a wildlife refuge. With over 2,000 acres, the Annex is by far
the largest protected open space adjacent to the ARRT. It is also the only
public open space parcel next to the trail within the Town of Stow. Most
of the Annex is forested, with white pine, oak, ash, red maple, black birch,
and cherry making up the majority of tree species. Wetlands occur on about
20 percent of the annex and include small streams, ponds, bogs, emergent
wetlands (i.e., dominated by herbaceous plants rather than shrub- or forest-dominated),
and vernal pools. The Annex is home to a wide range of wildlife species
and provides a rest stop to many others in migration. Annex lands continue
on our right as far east as White Pond Road and a few hundred feet beyond
into Maynard. These federal lands are a tremendous natural resource.

To our left, we continue to pass extensive wetlands along
the Assabet River. The only turn off Track Road is a driveway to the left
that leads to Crow Island. The island hosts a small, private airport and
runway, which also has been a soccer field. Crow Island was mined for sand
and gravel deposits, as were other sites along the river. North of the
river is a large, Town-owned open-space parcel containing a Town well and
the Town forest. The combination of these pristine, wooded lands, the river,
and the Annex to our south makes this the most wild and natural place along
the ARRT.

Elizabeth Brook joins the Assabet River close to the Stow-Maynard
line. Labeled as Assabet Brook on the USGS topo-map, it drains most of
central Stow and is the largest tributary to the Assabet River.

Representative species present along the ARRT:

Plants:

Trees

Red, White, and Silver Maples

Sugar Maple

Black and white Willow

River and Gray Birch

Hemlock

Swamp White Oak

Red and White Oaks

Pignut and Shagbark Hickory

White Cedar

White Pine

Quaking Aspen

White Ash

American Beech

Black Cherry

Shrubs

Buttonbush

Elderberry

Highbush Blueberry

Arrowood

Sweet Pepperbush

Meadowsweet

Swamp Azalea

European Buckthorn

Winterberry Holly

Speckled Alder

Silky and Gray Dogwood

Black Chokeberry

Yellow Flag

Blue Flag

Jewelweed

Purple Loosestrife

Cardinal Flower

Pickerel weed

Arrowhead

Arrow Arrum

Joe-Pye Weed

MarshPlants

Common Cattail

Tussock and other Sedges

Great Bulrush

Soft Rush

Wild Rice

Reed Canarygrass

Royal and Cinnamon Ferns

Marsh and Sensitive Ferns

Animals:

Birds along wooded riverbanks

Belted Kingfisher

Common Flicker

Downey Woodpecker

Yellow Warble

white-breasted Nuthatch

Tufted Titmouse

Black capped Chickadee

Wood Thrush

Gray Catbird

Cedar Waxwing

Northern Oriole

Common YelIowthroat

Tree Swallow

Common Grackle

Birdsnearfieldsormarshes

Bobolink

American Woodcock

Song Sparrow

KilIdeer

Barn Swallow

Cuckoo

Flycatcher

Wren

Indigo Bunting

Catbird

Birdsnearmarshes

Great Blue Heron

Green-backed Heron

Red-winged Blackbird

Marsh Wren

American Bitten

Egret

Rail

Bittern

Coot

Gallinule

Wood Duck

Black Duck

Mallard

Ring-necked Duck

Canada Geese

Gadwall

Shoveller

Green-winged Teal

Sphagnum Moss

Blue-joint Grass

AquaticPlants

Yellow Pond Lily

White Water Lily

Pickerel Weed

Watershield

Duckwceed

Water Clover

FeatherySubmerged Plants

Low Watermilfoil

Common Elodea

Ribbon-leaved Plants

Water Celery

Upland MeadowPlants

Sweet Fern

Sedges

Lowbush Blueberry

Beaked Hazelnut

Hayscented Fern

Canada Lily

Lady Slippers

Grasses

Forbes

Reptilesand Amphibians

Hognose Snake

Eastern Box Turtle

Snapping Turtle

Painted Turtle

Spotted Turtle (on special concern list)

Eastern Garter Snake

Northern Water Snake

Amphibians

Bullfrog

Toads

Green Frog

Wood Frog

Tree Frog

Red-backed Salamanders

Spotted Salarnanders

Red-spotted Newt

Leopard Frog

Pickerel Frog

Crustaceans

Crayfish

BirdsofPrey

Bald Eagle

Screech Owl

Barred Owl

Great Homed Owl

Fish

Largemouth Bass

Black Crappie (Calico Bass)

Brook Trout (stocked in tributaries)

Pickerel

Bluegill

Brown Bullhead

MammaI

Red and Gray Fox

Little Brown Bat

Beaver

Muskrat

Raccoon

Skunk

Mink

River Otter

White-tailed Deer

Little Brown Bat

Mice, Shrew, Rats, Voles

Chipmunk, Moles

Porcupine

Coyote

Moose

Red and Gray Squirrels

Woodchuck

Opossum

Long-tailed Weasel

Eastern Cottontail

Insects

Dragonflies

Green Darner

Twelve Spot Skimmer

Blackwinged damselfly

Common Forktail

Bluet

Sympetrum

Aquatic Inseet Nymphs

Dragonfly Nymphs

Damselfly Nymphs

OtherAquatic Insects:

Whirligig Beetles

Water Boatmen

Water Striders

Maynard

As we cross White Pond Road, we enter Maynard. Tuttle
Hill and the forested lands of the Fort Devens Annex are to the south;
a few houses sit between us and the Assabet River to the north. The next
two thousand feet of trail is the most natural and picturesque in ARRT's
passage through the Town of Maynard. Though privately owned, some maps
refer to this stretch as Riverside Park."

Once past the houses, the river flood plain is populated
by a red maple wetland. A number of small drainage swales direct runoff
under the trail into this resource. A portion of this red maple wetlands
is protected land owned by the Massachusetts Department of Environmental
Management.

Taylor Brook and Thanksgiving Pond to our right offer
some of the most scenic vistas along the ARRT. Extensive marsh, open water,
and minimally developed land adjacent to the Devens Annex Wildlife Refuge
provide a rich mix of habitats.

The Maynard Department of Public Works is located on our
right after we pass Thanksgiving Pond.

The next significant natural resource is the Assabet River,
which we cross in downtown Maynard at Riverfront Park behind the Post Office.
This point marks the lowest elevation along the ARRT of roughly 170 feet
above mean sea level.

As we head north out of downtown Maynard, it is not until
after we've crossed Acton Street that we begin to observe vestiges of a
more natural world. This takes the form of a vast wetlands plain to the
west of the ARRT, which spans the Maynard-Acton line.

Though Maynard is perhaps the most densely urbanized of
the five ARRT communities, ironically, it has the greatest number of publicly
owned open-space parcels along the trail corridor. While generally too
small to provide much habitat value for wildlife, each small green space
along the ARRT in Maynard contributes important breathing room for the
Town's human inhabitants.

Acton

The southernmost portion of the ARRT in Acton is flanked
on each side by Red Maple Swamp. These wooded wetlands give rise to a brook
that flows under the trail, under Rte. 27, and eventually joins Pratt's
Brook. We are within a Groundwater Protection District Zone 3, which means
that Acton's zoning bylaws set some limitations on land use activities
that would be detrimental to groundwater purity. This red-maple swamp is
also within the 100-year flood plain.

As we proceed north on the trail, first passing commercial
properties, then passing homes on the right, the trail rises gently out
of the flood plain and wetlands and becomes surrounded by second-growth
forest. Trees include red and white oaks, white pine, black birch, hemlock,
red maple, white ash, and northern red cedar.

Soon we see a hay field to our left. This is a special
attribute for the proposed trail. It and other agricultural lands to the
west of Fort Pond Brook Mill Pond are the only actively farmed land along
the ARRT. Fields and their wooded edges are important for wildlife such
as rabbits, moles, mice, woodchuck, pheasant, and a variety of songbirds.

In the vicinity of Sylvia Street we pass through a cut
created by the railroad to ease the grade. The soils of the Stonefield
Farm to our west are classified as 'Prime Farmland" and State or locally
important farmland." These good soils vary with poorly draining areas of
glacial till that were deposited by the glacier's retreat 10,000 years
ago. Till is a compact mixture of sediment composed of a wide range of
grain size - from very fine clay particles to large granite boulders -
that were compressed by the glacier.

Soon the trail is once again flanked by wetlands. These
provide the natural transition to Mill Pond, which was created by damming
Fort Pond Brook. The Mill Pond and its surroundings are strikingly beautiful.
A trestle crosses the pond, offering a pleasant resting point. Fish such
as largemouth bass and perch reside in the pond, and waterfowl including
great blue heron, wood duck, osprey, and mallards are occasionally observed.
Beaver activity has been reported in the Fort Pond Brook drainage basin.
The brook that enters Mill Pond to our West is an important wildlife corridor.
The Town's Open Space Action Plan proposes the establishment of a greenbelt
along Fort Pond Brook. White-tailed deer and eastern coyote travel along
these types of corridors. The area around the Mill Pond, with its wetlands
and floodplain, is part of the Groundwater Protection District Zone 3.
Fort Pond Brook ultimately provides water that goes into the aquifer that
supplies the Lawsbrook well field a few miles to our east.

The trail continues north, along the edge of Mill Pond.
Were we to continue around the pond and hook back (south, hugging the embankment
of Main Street), we would arrive at the half-acre, Town-owned park called
Mill Pond Recreation Area. This parcel is the only Town-owned land adjacent
to the ARRT in Acton. It is near the 1898 stone dam that impounds the Mill
Pond.

Though the Assabet River Rail Trail terminates at the
MBTA commuter rail a few blocks to our north, the land that provides our
connection to that terminus is fully urbanized. The Mill Pond Recreation
Area marks the end point of significant natural resources to be encountered
along the ARRT.

References

The following sources were drawn upon to prepare this
guide. They are great resources for additional information about the natural
treasures along the Assabet River Rail Trail: